I literally just cleared Chapter 7. I think I spent my whole day just trying to get past the fight with the huge tank. The part with Selvaria is actually quite easy seeing as the AI isn't too smart. Gather all the lancers to the bottom half of the map and hide behind all the ruins. Selvaria only goes so far before she stays put. As long as you don't get in her line of fire your cool.

I actually lost my first team member in that fight which was one of the snipers. Its pretty deep watching the screen fade to white as you watch them die. I'm pretty sure that triggered the old man in the cemetery to give me a new Order though (it coincidentally was one linked to snipers).

I think fights are a tad too long in this game. Spending an hour on one fight to then die and head back right to the start is pretty disheartening.